The present invention generally relates to apparatus and methods for replacing large and heavy elements in aircraft landing gear and taxi systems.
Aircraft systems typically are constrained by weight and size. Landing gear (LG) systems are no exception to this. LG systems, in fact, are a particular concern, since they are only used when aircraft are on the ground and to taxi the aircraft. The LG and undercarriage are a relatively heavy part; being as much as 7% of the takeoff weight, but more typically 4-5%.
Electrical, hydraulic and air turbine solutions for landing gear systems have been considered. For instance, electrical solutions are most common today. These require a high power traction electrical motor and gear box at the LG, as well as an electric generator for conversion and conditioning of the necessary electric power, powered by the aircraft's auxiliary power unit (APU). In addition to weight, the large, heavy electronic portion of the system occupies valuable space in the cargo bay.
Granted, many aircraft have APU driven electrical generators for other purposes, but adding weight for the electrical motor and gear box in the LG, copper electrical cable to the LG, and other considerations like upsizing the generator to handle additional electrical and thermal loads must be considered.
Hydraulic motors in LG systems have similar added weight and complexity concerns. And air turbine solutions require high velocity air flow, requiring a special APU driven compressor and routing the high pressure air to the LG. In sum, weight and size for existing solutions and their ancillary concerns remain challenges.
As can be seen, there is a need for replacing large and heavy elements in aircraft landing gear and taxi systems.